From
an interview with Paul McGillion: “It was really great - a difficult episode, but really interesting and different. It’s just Joe [Flanigan] and myself. David [Hewlett] and I have a couple of scenes at the start and the end of the episode, but throughout the whole episode it’s just Beckett and Sheppard. We’re the only main cast in the episode...
I guess I'll have to start paying attention again. :)